The present invention relates to automobile vehicle locks.
Locks mounted on a vehicle door are used to keep the automobile vehicle door in the closed position. Locks typically allow the door to be opened by operating either inside or external manipulators linked to the lock and able to be operated by a user. The locks include a claw mechanism designed to selectively set the position of cooperating means mounted on the vehicle with respect to the lock or release the cooperating means. Opening the lock involves disengagement of the claw from these cooperating means, allowing the door to be opened. Closing the lock involves keeping the cooperating means set with the claw in the lock, thus preventing the door from being opened. The claw mechanism is urged into its closing position by the cooperating means when the door is being closed. A pawl prevents the claw from returning to its release position, keeping the lock in the closed position, until the lock is subject to external action.
For purposes of this application, locking of the lock involves preventing the lock from being opened by using an external release control. Unlocking is the reverse operation, allowing the lock to again be opened when the external release control is manipulated. In the case of an automobile vehicle door, these operations are conventionally performed using a fascia pull or electromechanical actuator. In the case of a hatchback door or trunk (both doors for purposes of this application), an interlocking device is also used for locking or unlocking purposes.
For purposes of this application, “security locking” involves preventing the lock from being opened by operating an inside release control when the door is locked. Security locking notably prevents a vehicle door from being opened using the inside release control after the window glass has been broken. “Security locking release” is the reverse operation, consisting in again allowing the lock to be opened by operating the inside release control. In the case of an automobile vehicle door, these operations are conventionally performed using a specific electromechanical actuator. Examples can be found in the Peugeot 406, year 2000 model, or the Audi A4, again year 2000 model, which use locks of this type. A child-proof feature prevents the lock from being opened from the inside regardless of whether it is locked or not. As known, this feature prevents a vehicle door from being accidentally opened from inside, to protect children and is frequently provided on the rear doors of vehicles. For a vehicle rear door, these operations are conventionally performed using a key cylinder or electro-mechanical actuator. The Volkswagen Golf, year 2000 model, or the Renault Laguna II, year 2000 model, adopts such a solution.
An override feature allows the lock to be opened and simultaneously, locking to be released, or, with the child-proof catch set, the lock to be unlocked by operating the inside release control. This feature allows a door lock to be released in the case of accident allowing a passenger in the rear of a vehicle with the child-proof feature set, to unlock the lock, allowing the door to be opened from the outside.
Mechanical and electromechanical locks exist, which implement one or several of the above features.
European Patent Application 0,694,644 discloses an automobile vehicle lock with electrical release. The lock is released electrically by operating an actuator powered by the vehicle battery. A backup energy supply is provided by a back-up battery installed in the vehicle door where the lock is installed. Should the electrical supply from the vehicle battery be defective, the lock can still be opened using the electrical power supplied by the back-up battery.
This solution does raise a problem in dimensioning the door lock release motor. The motor should not only allow the lock to be opened under normal conditions of use but also under degraded conditions, for example after impact. The ratio between the force needed under degraded conditions and the force needed under normal operating conditions may be of on the order of 3:1. As and example the force may typically change from 300 N to some 1000 N. The motor and its speed reduction gear are consequently designed to ensure release under degraded conditions which leads to electrical and mechanical over-dimensioning of the motor with respect to normal use requirements. Motor dimensioning also creates a problem for the back-up power supply. The back-up power supply needs to be capable of supplying sufficient energy to ensure release under high loads.
The lock used in the Renault Laguna II has a claw mechanism operated by an assembly consisting of a pawl and pawl lifter referred to hereunder as a pawl assembly. The lock has separate inside and external release levers. A release coupling lever is inserted between a bearing surface on the external release lever and a bearing surface on the pawl assembly. When the release coupling lever is in position between the bearing surface on the external release lever and the bearing surface on the pawl assembly, rotation of the external release lever causes the pawl to rotate and the lock to open. When the release coupling lever is not in position between these bearing surfaces, turning the external release lever has no effect on the pawl, and the lock is locked. A second release coupling lever is inserted between a bearing surface on the inside release lever and a second lever which is engaged with the pawl assembly. The second release coupling lever operates similarly to the first one, withdrawing it ensuring security locking or activation of the child-proof feature. Insertion releases security locking or deactivates the child-proof feature. Override is ensured when the security locking feature has been released via a cam controlled by the inside release lever. Displacement of the cam causes the first release coupling lever to become inserted between the bearing surfaces on the external release lever and the pawl.
When the lock is motor driven, the first release coupling lever is operated by a first motor for locking or unlocking the lock. The displacement of the first release coupling lever is also controlled mechanically and by an interlocking device. The motor has no back-up power supply. A safety button on the edge of a door makes it possible, in the case of an electrical failure or flat battery, to lock the lock, and then close the door in order to abandon the vehicle with the door locked. A second motor operates the second release coupling lever allowing security locking, or release of security locking or activation or release of the child-proof feature.
In this lock, only locking, unlocking, security locking, release of security locking and activation or deactivation of the child-proof feature are provided by electric motors. Release remains otherwise purely mechanical.
European Patent Application 0,589,158 discloses a lock in FIG. 2 with an electrical release actuator that operates on a pawl. The actuator is triggered by contacts provided on external and inside release controls. A rotary lever has a rest position and an active position. The electric release actuator allows the rotary lever to be brought from a rest position to the active position. The rotary lever is mechanically connected by cables to the external and inside release controls. In the rest position, the rotary lever does not act on the pawl. In the active position, the rotary lever is adapted to act on the pawl when it is driven mechanically through the inside and external release controls. A back-up power supply powers the actuator should the vehicle battery fail. The lock is thus an electrically-opened lock when the electric release actuator does not act on the pawl. In such situations, mechanical release using the rotary lever is declutched. In the case of a collision or failure of the vehicle battery, the electric operating actuator acts on the rotary lever to bring it to its active position, and the lock is opened mechanically.
This solution has some disadvantages. As an example, should the electric release actuator fail, the lock cannot be opened either electrically, or mechanically. The same applies when the electrical wiring to the door is cut so that the actuator is no longer connected to the vehicle battery, nor to the standby battery. The danger of self-release is managed by electronic redundancy based on speed information. However, this solution may prove insufficient when parking on a slope.
European Patent Application 0,598,158 further discloses a movable, spring-biased electrical release actuator body. A cable system allows the electrical release actuator body to be moved axially in order to operate on the pawl from the external release control and inside release control. Thus, even in the presence of electrical failure, it is possible to release the lock mechanically and shift the actuator body. The cable system is only operated when the displacement travel of the external release control or the inside release control is greater than the length of travel required to trigger the sensors that control electrical release. In this embodiment, the lock is an electrically and mechanically opened lock. Neither electrical release nor mechanical release can be selectively coupled.
The European Patent Application 0,598,158 does not discuss how the locking, security locking, child-proof feature or override functions are implemented. As mechanical release is always enabled, action that is too fast or too violent on the release controls leads to simultaneous electric and mechanical release, which can damage the electric release actuator.
European Patent Application 0,828,049 discloses a lock with a coupling member mechanically driven by cables connected to inside and external release controls. The coupling member is rotatively mounted on the same axis as the pawl. A coupling slide member can move in translation between a coupling position and a retracted position. In the coupling position, the coupling slide member transmits rotation of the coupling member to the pawl. In a retracted position, rotation of the coupling member has no effect on the pawl. In this way, the lock ensures locking, child-proofness and security locking. An auxiliary electric drive is used for driving the coupling member or the pawl. The auxiliary electric drive is controlled on the beginning of travel of the release control.
The above described solutions have some disadvantages. As an example, if the auxiliary electric drive drives the coupling member, the lock is an electrically-assisted mechanically released lock. Action that is too rapid or too violent on the release control will lead to simultaneous electrical and mechanical release. The simultaneous release may damage the auxiliary electric drive. If the auxiliary electric drive is blocked, the lock can no longer be opened, electrically or mechanically.
The assumption where the auxiliary electric drive is responsible for driving the pawl is not disclosed in detail. With this assumption, if the auxiliary electric drive becomes blocked, the lock can no longer be opened, electrically or mechanically.
International Application WO-A-01/66889 discloses a lock having an electric motor, which is designed to rotatively drive an eccentric stop member via a coupling. The coupling can be selectively coupled by means of a release coupling lever so that the motor drives the eccentric stop member. When the selective coupling is not engaged, the motor does not drive the eccentric stop member. The eccentric stop member acts on a positioning lever that acts on the pawl. The coupling lever is driven by an inner operating lever and by an external operating lever, respectively driven by the external release control and inside release control. In normal operation, the lock opens electrically when the coupling is established by operating either of the release controls, the corresponding operating lever and the coupling lever. A safety release feature, not described in detail, allows direct action of the inside or external operating lever on the pawl, through supplementary travel of the release controls.